With that in mind Michael Andersen, Lillian Karabaic (our wonderful producer) and I tackled the topic of lights in the most recent episode of the BikePortland Podcast.

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We were joined in studio by Halley Weaver, author of the Bikeleptic blog. Halley is not only an everyday bike rider, she also has photo-sensitive epilepsy, a condition that impacts her riding experience. For instance, she’s been a volunteer for the Portland World Naked Bike Ride for the past six years, but she can’t actually participate in the ride because of all the blinking bike lights used by the thousands of participants.

In this episode, Halley shares the straight dope on how your light choices can have serious health impacts on her and other road users with epilepsy — and how to make bike lighting choices that can minimize those impacts.

We also discuss the science behind nighttime visibility, the lack of lights as standard equipment on bikes sold in the U.S., and much more.

NOTE: We love your comments and work hard to ensure they are productive, considerate, and welcoming of all perspectives. Disagreements are encouraged, but only if done with tact and respect. If you see a mean or inappropriate comment, please contact us and we'll take a look at it right away. Also, if you comment frequently, please consider holding your thoughts so that others can step forward. Thank you — Jonathan

It’s my instinct to not use blinky lights. The front one disorientated me, and is much more useful as a solid, path illuminating, beam.

When I was first in town, I caught a ride with a part time bike commuter in her car, I remember her saying “I get it, I see you, do you also have to give me a seizure?”

Focusing more on the fact that it annoyed drivers, I decided to not use the blink function on the rear either. Drivers are generally in an altered state, operating a weapon at high speeds. The experience drains money from them by the minute. I don’t want to piss them off any more than I need to.

But seizures are a really good reason too.

Visibility wise, there is no mistaking a bright stable taillight for something your car should hit.

Their early work was a little too new wave for my tastes, but when Sports came out in ’83, I think they really came into their own, commercially and artistically. The whole album has a clear, crisp sound, and a new sheen of consummate professionalism that really gives the songs a big boost. He’s been compared to Elvis Costello, but I think Huey has a far more bitter, cynical sense of humor.

But seriously, if you don’t know the feeling of road hypnosis, you’re either not a driver, unaware of yourself in general or being dishonest.

If you haven’t experienced these financially drained, easily agitated operators of machines that kill more people than guns each year, going on a road rage tare. You might want to pay more attention. (Source:NYC car owner/operator for over a decade)

Or just keep gripping that steering wheel tightly, gritting your teeth, thinking about what your boss said earlier that day. Roll the windows up, turn the AC on, get lost in a song on the radio and end up with with a vehicular manslaughter charge.

Jonathan, can you document that Germany has banned blinking lights (as you say in the podcast)? What I’ve been able to find says that Germany allows an optional blinking rear light in addition to the mandatory solid red rear light.

I think they’re against the law in many countries. I never once saw a blinking light (that I recall) for the 3 months I was in the Netherlands. Most lighting there is dynamo-powered. Never saw blinkies in Germany either.

The excerpt below is text from the German law that Lily brought to the podcast. She read some of it on the air but I’ve pasted it in its entirety below (emphases mine):

A white headlight and a red rear light are required and must be ready for use at any time. The headlight and rear light must be turned on with a single switch. They must be able to be powered by a dynamo backup, though they can use batteries in addition (as a standlight for example). One additional battery powered rear light may be added at the most; further battery powered lamps are not permitted, including blinking ones or ones on the helmet or body. Racing bikes (in Switzerland 700c x 23 or thinner) up to 11 kg weight (24.25 lbs or 12 kg/26.45 lbs in Austria and Switzerland) are not required to have the dynamo lighting, but may use removable battery powered lights. These lights must be carried at all times. All lighting needs an approval stamp from the German department of transportation in Flensburg – see the image at top or your own B&M LED lamps. Incidentally, the lights that are permitted don’t have a setting for blinking.

I’ve cycled without lighting countless times and have never once felt unsafe. While I use lighting during my winter commutes, I do so to see the road. I’m not at all convinced that bicycle lights are necessary in an urban environment where roads are lit by street lights.

As far as I can tell there is little evidence that bicycle lighting significantly reduces risk in urban areas. And there is some evidence that lights could under some circumstances increase risk (moth effect).

Pedestrians are at greater risk than cyclists in most cities but they are not required to wear lighting. Why is there a double standard for cyclists?

I would like to emphasize that while the Netherlands requires cyclists to use lighting, many people cycle without lighting. Despite this blatant flouting of lighting requirements cycling at night in the Netherlands is incredibly safe.

It has never been sufficiently studied whether carrying bicycle lights by cyclists actually benefits road safety; therefore, no clearcut conclusions can be drawn about this issue.

In the US, I don’t see it as a double standard. Bikes are classified as “vehicles” (even if we argue otherwise), follow laws as such, and occupy space in the road. With bikes being on the road — even when there is a bike lane — they are not truly separated from car traffic. Not taking into account the too-many places that sidewalks/marked crosswalks do not exist, pedestrians are typically on a sidewalk (where cars don’t drive) or in a crosswalk (where cars are supposed to stop for them).

In practice bikes are not treated as motorvehicles. They are required to use an extensive network of mandatory sidepaths and when these sidepaths are not present they are required to ride as far right as is practicable (or use the sidewalk). Moreover, as the prevalence of jaywalking/biking shows, pedestrians and cyclists habitually violate motorist-centric laws with near legal impunity.

Both pedestrians and cyclists are at highest risk when they enter the road way at intersections. If bicycle lighting is truly effective then it seems odd to not mandate lighting for pedestrians as well.

“as the prevalence of speeding/eating/texting/driving while under the influence/failure to obey traffic control devices/failure to maintain a lane/worn, broken or missing equipement/front, rear, and side impact collision, rollover single and multiple vehicle accidents show, drivers habitually violate motorist-centric laws with near legal impunity.” 😉

Not at all to argue with the point you were making, I just thought that was an amusing corollary for motor vehicle operators.

The point is not to mandate the use of lights based on some proven effectiveness ( for that matter, a bike is a vehicle, a pedestrian is not a vehicle. If you don’t want to be treated like a vehicle, don’t act like one ). Lights increase your visibility. If you don’t want to use one, that’s fine, but you need to give up the notion that everyone else should share your same preferences.

I guess you missed the part where I stated explicitly that I use lights. And it’s interesting that no one here has provided evidence that the use of lights significantly reduces risk in urban environments.

Risk to people riding is reduced, the more easily road users operating motor vehicles are able to see people riding bikes on the road. Jakes remark specifically addresses the subject of this story, which is about the question of hazards it’s thought that blinking bike lights possibly may pose to people that are susceptible to seizure episodes.

An additional, good question to him would be how helpful in seeing people on their bikes, he finds steady bike lights to be compared to blinkies.

I caught that part, but you made a point of saying that you use light exclusively to illuminate the road and if you could see you wouldn’t use them, and that they basically weren’t necessary.

I’m not remotely surprised that someone would read your first post and think that you were against people using lights. If that wasn’t your intention, you might want to work on your tone.

For many of us it just seems sensical that a car or pedestrian (or other bike) would see us at night when we have a light on our bike versus not having one. Makes complete sense to me (and I also would agree with the above post about being able to see lit cyclists better when driving or riding (remember headlights/bike lights usually only point one direction)).

so i question the evidence that lighting increases cycling safety in well lit urban areas* (clearly indicated in my initial comment) and the response is anecdotes? i think my skeptical tone is merited.

i have absolutely no problem with people using lights, helmets, hi-viz, or even 6 foot red safety flags if these things make them *feel* safer. however, when claims are made that these things *are* safer i want to see some actual evidence. moreover, i believe that mandating safety devices for active transport users makes these activities seem dangerous and abnormal. i also believe that when it comes to safety we should emphasize “not hitting pedestrians and cyclists” versus victim blaming (were they wearing a helmet and did they have lights).

*i expect that lights do increase safety in dark areas or on high-speed rural/suburban roads.

So can I create evidence by going out on my street at night? You’ll stand two block away wearing dark clothes and I’ll compare how easily I can see you with a light shining at me, or no light. I”m going to go out on a limb and hypothesize that I’m going to see you better with the light (and my house is pretty much directly under a streetlight).

Kari, thank you, yours is a fair summary of peoples’ use of bikes on the road as compared to people’s use of the road on foot as pedestrians. Given that they’re not road users in the sense that people using vehicles are, there generally isn’t nearly the need for people on foot to be legally required to display reflectivity and lighting that there is for people riding bikes.

As for the potential hazard blinky lights may pose in bringing about seizures in people susceptible to them, thats something I’m interested in getting a better understanding of. I may be able to ask a family member with a history of seizures, for their take on this. Big groups of riders close together, all with blinkies going, seems at the least, very annoying. I’d want to know more about how much the occasional rider with a blinkie, or those spaced far apart, pose a threat of seizure to those susceptible to them.

The German Cyclists’ Federation ADFC has studied the subject of bicycle accidents at dusk and in the dark in Europe…

1/3 to 40% of cyclists ride in the dark without lights or with partially defective lights.

This suggests that the different rules have only amarginal impact on the safety of bicycle traffic in the dark. Only a small number of nighttime accidents can be clearly attributed to the lack of lights: Other major risk factors are driving or riding under the influence of alcohol, high- er driving speeds on empty roads at night and impaired night vision especially in older drivers.

I think Ms. Weaver vastly overstates the prevalence of epilepsy when she claims that 10% of the US population suffers from it.

Prevalence and Incidence Epilepsy is the fourth most common neurological disorder in the United States after migraine, stroke, and Alzheimer’s disease. About one percent of Americans have some form of epilepsy, and nearly four percent (1 in 26) will develop epilepsy at some point in their lives. The number of Americans who have epilepsy is greater than the number who have multiple sclerosis, Parkinson’s disease, and cerebral palsy combined. 10% of Americans will have at least one seizure at some point in their lives.

I haven’t listened to the podcast yet but if I said 10% of people in US have epilepsy, that is totally my error and not intentional! You have the correct data! The 10% is of people who will experience seizures in their lifetime as you quoted.

It’s also important to note as I hope didn’t get edited out that many seizure disorders aren’t epilepsy. I have a listing of almost 40 seizure disorders on my site that I compiled if interested. And then also affected but not in my realm of study so much (maybe in the future) other neuro disorders such as migraines, autism, ocular degenerative diseases etc.

I use a blinking 600 lumen light during my commute, mostly in the mornings, and during daylight hours. I do this because it seems to be the only thing that makes car drivers stop before pulling out in front of me. I know it may be considered an obnoxiously bright light by other cyclists, and I truly regret that–but I don’t want to get hit by a car, and usually I’ll have at least one car a day pull in front of me when I don’t have the strobe light on.

I like having lights on my bikes, but I wish more cyclists paid more attention to the context. When riding with cars in the city, bright blinking lights help us stand out among all the other lights… and oncoming cyclists are at least 20′ away on the other side of the road. But on paths we don’t really need extra bright lights, and oncoming cyclists are almost directly ahead. I am routinely almost blinded by cyclists on the Springwater who fail to turn their lights to a lower setting or aim them away from my eyes.

Amen, brother Andrew. I always shield my light when riders approach. I sure wish everybody else would. Lights aimed straight and level into others’ eyes destroy their night vision, which takes many minutes to recover, but usually just can’t due to continuing exposures. Lights should be aimed at the road surfuce.

Was observing an emergency strobe just today (the one on the lights, not the one on the vehicle) and saw it doing a cycling that look like flash-flash-pause, flash-flash-pause — and a nice long pause, perhaps as much as a second. Don’t know what’s on the vehicles — it could be IR.

The problem with “random strobes might be okay” is that a photosensitive person is not going to stare at the light long enough to say “aha, that light is random, that will not trigger me”. They’re going to go “F, a strobe, G D it, close my eyes or turn away, F-ing insensitive A-holes and their strobes”. This is not the sort of experiment that anyone is eager to run. Similarly, they are not going to try to take the time to estimate the flash rate to see if is they one they care about. “This strobe is too slow, this strobe is too fast, this strobe is juuust right — oops.”

Furthermore, the set of strobe-bothered people also includes those who are merely potentially photosensitive — i.e., people with epilepsy, temporary or permanent, where their doctor says (and they probably all say, and mine did, after a head injury) “you probably want to avoid strobing lights”. The “or else” has teeth.

I definitely agree re. strobing lights on multi-use paths (applies also to overly bright non-strobing lights that aren’t pointed down at the ground, unless they have a dipped beam to start with like some dynamo lights). It’s impossible to see what you are headed into when passing someone going the other way with one of these lights at night on a dark path – for example a pedestrian on your side of the path, and the strobing in the dark is particularly hard to look at.

600 flashing lumens sounds a bit excessive anywhere to me! For not being pulled out into, a helmet-mounted light seems to work ok to me; it doesn’t get hidden behind parked vehicles near intersections so easily, and you can aim it a bit (I turn it off on the Springwater!)

I strongly agree. Bright lights that are okay on well-lit busy city streets are painful and even dangerous to other cyclists on paths like the Springwater. Please (!) use a low setting and aim lights down and to the right when you are coming toward me on a path.

When I’m a driver I find it easier to identify cyclist when they have blinking lights, esp. In poor weather. The high power front lights are painful to look at, but more power to you for getting noticed. Speaking of bike safety. I keep seeing people wearing helmets incorrectly. Loose straps and helmets tipped up and back so that it’s past their hairline.

Jake, if you can venture your thoughts on this, how well in comparison, do you find that bike lights on steady, or non blinking mode help you identify cyclists, or distinguish them from the background against which they’re riding, and in bad weather?

If people riding were to turn to the use of steady lights instead of blinkies, would you think that would increase the risk of their not being seen by road users operating motor vehicles?

Yes, but lights that are suited to city streets should be turned low and to the right when on paths like the Springwater. Please don’t blind me on a narrow path (where there is no need to grab the eyes of drivers).

I use lights at night (and sometimes during the day). When I have occasionally ridden off during daylight hours and then found myself out after dark without lights, my first concern has always been getting a ticket on the way home, not visibility.

I use a red light that alternates between 5 LEDs but doesn’t change between fully on and fully off for my rear light, and my front light has a pattern that blinks twice quickly, holds on the second blink for a while, and then slowly fades it down to black before starting again.

I’m guessing neither of them has the potential to trigger a seizure in anybody, although I haven’t tested that yet, and they’re certainly much less annoying to look at. However, they are much more noticeable than a steady light and the front actually draws a pretty good compromise between getting attention and throwing enough light on the road surface that I can see potholes in dark areas.

Since I have to put up with 200 decibel motorcycles 24/7, for their “safety” …..I will keep my blinking lights, thank you very much. 8 years of cycling commuting experience has taught me the more annoying the light, the more chance I will make it to where Im going….

The lights are manufactured with the capacity to strobe. If there is strong evidence that this is medically a problem, then action should be taken to change this. This may take some doing by those sensitive to blinking (e.g., American Epilepsy Society), and will certainly required some strong medical evidence. OTH – I agree that cars more readily stop when they see the blinking light and less likely to pull out in front of me – at least in the USA. I have ridden in Denmark – where biking reigns supreme. Bikes are an expected part of the environment and drivers are far more vigilant. We were never harassed and never had cars pulling out in front of us. I never felt a need to have any day-time lights and never saw them on others. Night-time lights did not blink. Finally – it is good practice, regardless of your bike setting, to keep it tilted to the road and not in the eyes of oncoming traffic.

So can I create evidence by going out on my street at night? You’ll stand two block away wearing dark clothes and I’ll compare how easily I can see you with a light shining at me, or no light. I”m going to go out on a limb and hypothesize that I’m going to see you better with the light (and my house is pretty much directly under a streetlight).

Oh, Lily also mentioned motorcycles. Some motorcycles do use pulsing lights (slower modulation than flashing or blinking) to increase visibility, and studies have been done that indicated improved safety (but the studies I saw on that were decades ago).

The higher frequencies are biggest issue for seizures. From 6 to 40Hz is the dangerous range. Keeping the frequency around low side, say 1Hz, would be best and still as or more affective. Emergency vehicles use flashing lights, they just use lower frequency ones, usually much less than 6Hz.

SeeSense in one light that uses a slow pulse, at a reasonable brightness, for steady state riding. When you make a turn or slow down, it briefly increases the intensity and brightness. I think the fact that its obvious the light correlates with bike movements potentially makes it useful. Drivers may pay more attention to lights that give them real information about movement, as do car break lights, versus just crazy fast high intensity annoying ones that remain the same all the time.

Maybe more bike lights should follow emergency vehicle frequency standards, adjust intensity for ambient light conditions, and focus on relaying information about changes in movement using accelerometers, light sensors, microwave motions detectors, etc. These sensors are mostly just a few bucks these days. Would be nice to have more light option like this. Smarter and less annoying.

Nobody will want to hear this: in my work, I escort down syndrome citizens around the outer east burbs on bicycles. Empirically derived, no amount or style or combination of lights make a significant difference in near misses by motor vehicles. What gets instant visibility, respect and civilty are safety vests.

Not buying it. Safety vests only works when at least some ambient light is available. When it’s pitch black out they are worthless. And yes, studies back this up – specifically the study showing that cyclists largely overestimate their own visibility to others.

Please stop spouting this kind of lousy advice. Lights are important if you want to be seen after dark. You can argue flashing or levels of brightness, but if you rely only on bright and reflective clothes you are on your own.

Conspicuity limitations make bicycling at night dangerous. This experiment quantified bicyclists’ estimates of the distance at which approaching drivers would first recognize them. Twenty five participants (including 13 bicyclists who rode at least once per week, and 12 who rode once per month or less) cycled in place on a closed-road circuit at night-time and indicated when they were confident that an approaching driver would first recognize that a bicyclist was present. Participants wore black clothing alone or together with a fluorescent bicycling vest, a fluorescent bicycling vest with additional retroreflective tape, or the fluorescent retroreflective vest plus ankle and knee reflectors in a modified ‘biomotion’ configuration. The bicycle had a light mounted on the handlebars which was either static, flashing or off. Participants judged that black clothing made them least visible, retroreflective strips on the legs in addition to a retroreflective vest made them most visible and that adding retroreflective materials to a fluorescent vest provides no conspicuity benefits. Flashing bicycle lights were associated with higher conspicuity than static lights. Additionally, occasional bicyclists judged themselves to be more visible than did frequent bicyclists. Overall, bicyclists overestimated their conspicuity compared to previously collected recognition distances and underestimated the conspicuity benefits of retroreflective markings on their ankles and knees. Participants mistakenly judged that a fluorescent vest that did not include retroreflective material would enhance their night-time conspicuity. These findings suggest that bicyclists have dangerous misconceptions concerning the magnitude of the night-time conspicuity problem and the potential value of conspicuity treatments.

It seems that in this study, the people in cars are treated as fixed, invariant, unproblematic, with no inquiry into their attentiveness, speed, sobriety, etc. The reason I bring this up is that the difficulty seeing people biking (in time) has–in my view–more to do with the speed and insularity that characterizes sitting inside an automobile than anything the person on a bike is doing/not doing. If someone else riding a bike has no lights and no reflective bits I can’t see him well on unlit streets from my bike either. But all the other variations mentioned I think would work fine for me as the person wishing to see the person on a bike.

The onus is always put on the person biking to ‘be visible enough,’ but this elides the (auto-bound) viewer’s handicaps which seem at least as important to me in this context.

Does the moth effect apply to emergency vehicles or cyclists or both. Also, as people have mentioned here before please be respectful of our homeless population and please turn down your lights. You may sacrifice your safety but at least you won’t annoy others.

I live in a rural forested area with no bike lanes on the pacific bike trail. I find that Blinking lights provide little visibility enhancement The rider wearing bright light clothing is the best visual enhancement. The blinking lights may actually be a negative because they do catch the eye of the driver. However in driving, the vehicle follows the eye. causing an inadvertent danger. The very bright blinking lights have been jokingly called epileptic sezure lights It seems that this was not such a joke. The use of very brite lights at night are a mixed blessing. maybe ok for the user, but terrible for the oncoming traffic. They also produce a contrast gradient that leaves areas not illuminated invisible. You must be able to ride within your cone of illumination Bright lights must be accurately aimed or they become a menace. Like lighten up and slow down

i use blinking front and back during the day/dusk–solid beam front and blinking rear when it is full-dark–also wear a yellow hi-viz jacket with huge reflective strips all over it AND have lights on my backpack. sometimes i even wear a helmet light–scandalous! i cannot tell you how many times i have almost creamed other cyclists who choose to ride ninja when it is dark–i frankly admit that i did not see them until the very last second, because, hey-it is dark out and they were all in black/dark colors. that infamous “no-viz” look. and they had the balls to curse me out. the majority of these unfortunates were not only riding ninja–but were also salmoning towards me!! i literally have no insight whatsoever into what made them think either practice was an intelligent choice to make. the downtown Waterfront MUP is the worst for safety-deficient riders–attracts them like ants to honey. after riding in PDX for only 4 years i admit i am pretty burnt out on being responsible for how everyone else conducts themselves on the road–not just myself. SERIOUSLY considering leaving PDX since bike transit is most likely going to decline and suck major as more people move here in the next decade.

I have installed magnetic induction lights on all of my family’s bikes. The Danish version (Reelight) is kind of pricey, but there are knock offs that seem to work fine too. The magnets are mounted on the spokes and the lights are mounted on the axles. They seem hard to steal. Different models can also be mounted higher with wiring. Ours flash at variable speeds as they are linked to the wheel movement. They also have a capacitor that keeps the flashing on the rear light for a couple of minutes leading to helpful people reminding you to turn your light off. I use it as an opportunity to spread the word about these great lights.

I also use a USB rechargeable on the handlebars and small lights front and back on my helmet and rear rack and lights for side visibility in both wheels. The front one changes color in a rainbow pattern. For reflectors I find the reflective whitewall tires to be great for side visibility, and I added reflective tape to my favorite metal pant leg clips.

I know it’s a bit excessive, but it’s also bike light art and small children have exclaimed as I ride by, which is fun.

RCW 46.37.280 declares that “flashing lights are prohibited except as required in [emergency situations], warning lamps authorized by the state patrol, and light-emitting diode flashing taillights on bicycles.” (Emphasis added.) The exemption for taillights confirms that bicycle headlights are included in the prohibition.

So, blinking front lights are illegal in Washington. I’ve never heard of anyone cited or hassled for them, but that seems to be the law.

I tried different types of blinking/flashing lights on my Cortina, but in this days is a normal steady beam better than before. Some years ago, the led’s were not as strong as now. The Sigma roadster is a perfect solution, for all kind of bicycles. Here in the Netherlands is a blinking or flashing light no problem at all. The most Cortina U4 models have LED with battery as front light, https://www.fietsweb.nl/nl/cortina-u4-transport This front leds can only give a steady lightbeam.